Port frontend to Svelte 5 and SvelteKit

[aumetra]

Should make things faster and hopefully more maintainable through simpler APIs.
Also SvelteKit is a nice DX improvement over raw Vue (and Nuxt).

Closes #443

[aumetra]

Look, I'm still torn between:

1. Svelte 5 and SvelteKit
2. Oxidizing everything and moving to either Leptos or Dioxus

Both are nice. But I think Svelte is more mature and will probably be faster and easier optimizable (especially since WASM for the browser isn't really easily splittable into smaller chunks)

And I feel like there are a lot of open-source frontend devs that like Svelte and would rather contribute to a Svelte codebase than to a Vue or Rust codebase. So it's also about appealing to potential contributors that help me fix up the mess that is the frontend (because, surprise surprise, I'm not a frontend dev)

[erlend-sh]

Leptos and Dioxus are still ostensibly in the R&D stage, so Svelte gets a +1 from me.

I say that even though we’re using Leptos in one of my own projects, but that’s because we specifically needed a WASM-based frontend, so it is itself a R&D project.

Leptos is aiming for a stable release of its major new 0.7 version around July, so that could be a good time for another look if the itch for complete oxidizing doesn’t subside 😆

[aumetra]

Handing the progress on this over to @vesdev (at least partially). I'll merge their progress once they tell me they are ready.

[nyabinary]

Look, I'm still torn between:

1. Svelte 5 and SvelteKit

2. Oxidizing everything and moving to either Leptos or Dioxus

Both are nice. But I think Svelte is more mature and will probably be faster and easier optimizable (especially since WASM for the browser isn't really easily splittable into smaller chunks)

And I feel like there are a lot of open-source frontend devs that like Svelte and would rather contribute to a Svelte codebase than to a Vue or Rust codebase. So it's also about appealing to potential contributors that help me fix up the mess that is the frontend (because, surprise surprise, I'm not a frontend dev)

+1 for Leptos personally :P